Certain manufacturing processes require the use of liquid chemicals such as acids, solvents, bases, photoresists, CMP slurries, dopants, inorganic, organic and biological solutions, pharmaceuticals, and radioactive chemicals. Often, these processes require a specific liquid chemical for each particular process. Furthermore, each process may require a specific liquid chemical at various stages of the process. Storage and dispensing systems in many instances are arranged to allow alternative containers to be used to deliver liquid chemicals to a manufacturing process at a specified time. Consequently, manufacturing personnel need to change the liquid chemical being used for the particular process at the specified time so that the system delivers the correct liquid chemical to the manufacturing process. It is critical that the proper liquid chemical be installed into the systems for the particular process. If the incorrect liquid chemical is installed for a particular process, personnel may be put at risk. Furthermore, equipment and the articles under manufacture may be severely damaged or even rendered useless for their intended functions.
Prior art systems have attempted to utilize unique pump connectors that will only fit with a correct container. Each container has a unique configuration based on the liquid chemical contained therein. The intention is that only the correct chemical can be used in any particular manufacturing process, because the process will dictate a unique pump connection and a corresponding container with the correct chemical liquid. One example of such a system is disclosed in Osgar et al., “Liquid Chemical Dispensing System With Sensor,” U.S. Pat. No. 5,875,921. The Osgar system uses physical configurations, called key codes, to prevent accidental dispensing of an improper liquid from a container. Both the container and a connector have unique key code configurations. The connector must have the same key code configuration as the container for the connector to be properly coupled with the container. The Osgar system also employs a sensor that senses proper coupling of the connector to the container. When the sensor senses a proper coupling of the connector to the container, a pump is enabled. When the container and the connector are not properly coupled, the pump is disabled.
Some prior art systems, however, do allow the pump connectors to be partially connected to the incorrect chemicals such that pumping can take place even though the connection is not proper. In addition, personnel still can attach the wrong chemical to the wrong process or at the wrong time. Such incorrect connections can be dangerous to personnel and have caused millions of dollars of damage to equipment and to articles of manufacture. A system that provides a reliable connection between the correct chemical and the correct process, and enables tracking of incorrect connection attempts by personnel would be a useful improvement over the prior systems.
In the fabrication of semiconductor devices, materials of varying purposes are deposited on a semiconductor substrate. The semiconductor substrate is often a wafer of monocrystalline silicon materials such as silicon dioxide. Materials deposited thereon may include copper, aluminum and other metals to form metal lines or other circuit features within trenches of the semiconductor substrate. Additional circuit features and material layers may be formed on the semiconductor substrate throughout the fabrication process.
In order to form trenches as described above, a photoresist material is first deposited above the semiconductor substrate. The manner of transport and delivery of the photoresist material to the semiconductor substrate may be critical to the fabrication process. For example, the cost of application of the wrong type of photoresist may be quite extreme. Such an error may cost in terms of a destroyed expensive semiconductor substrate, such as a circuit device wafer, wasted photoresist, and the downtime necessary to correct the error.
The photoresist material described above is transported and delivered to the surface of the semiconductor substrate in a liquid form. The photoresist material is applied and thinly spread across the semiconductor substrate surface generally by a spin-on process. Parameters of the spin-on process are selected to ensure a fairly uniform, thin distribution of the photoresist across the surface of the semiconductor substrate. This is often followed by application of heat to the semiconductor substrate resulting in the formation of a solid photoresist layer on the semiconductor substrate.
The solid photoresist layer described above may be patterned to allow for the formation of trenches therebelow by conventional etching techniques. However, proper trench formation and uniformity is dependent in part upon the degree of uniformity displayed by the thin photoresist layer defining the trenches. Indeed, proper transport and delivery of photoresist material to the semiconductor substrate is critical to the fabrication of a reliable semiconductor device. In fact, as device features, such as metal lines, become smaller and smaller, the adverse effect of photoresist non-uniformity on a device feature becomes magnified.
Achieving a uniformly thin photoresist layer may require application of a spin-on, or other process, which employs parameters based on the particular physical and functional characteristics of the photoresist material. Unfortunately, characteristics of a photoresist material type may vary from one batch to the next. For example, the viscosity of a photoresist type may vary from one batch or container to the next. Thus, establishing reliable predetermined parameters for forming an adequately uniform photoresist layer on a semiconductor substrate may be extremely difficult, if not impossible, to accomplish. Proper transport and application of photoresist material to the semiconductor substrate faces challenges related to both providing the proper type of photoresist material, and employment of the proper application parameters in light of precise characteristics of the photoresist material provided.